Amazon.com says it won't fill the orders of customers who took advantage of a pricing error on its U.K. site to buy iPaq handheld computers for less than $12 on Wednesday.

The company said that its terms of use strictly state that no contract for sale has been formed until customers receive an e-mail stating that their order has shipped, meaning it has no obligation to hand out Hewlett-Packard iPaqs at rock-bottom prices. "We will be canceling orders made for the HP iPaq Pocket PCs at the incorrect price this morning," the company said in a statement.

The iPaq H1910 Pocket PC, which retails in England for about $449 including the value-added tax, appeared on Amazon's U.K. site for $11.45 by Wednesday morning and remained on the site through the morning. That was long enough for the word to spread through online forums. By shortly after 11 a.m. Greenwich Mean Time, the iPaq was listed as the site's No. 1 seller.

Customers were also able to order an iPaq H5450--normally priced at more than $780--for $40.

Shortly afterward, the entire site was taken offline without explanation. Visitors to the home page were greeted with a generic message that read: "We're sorry, but our store is closed temporarily. We expect to be back soon." The message noted that Amazon's U.S. site was still open for business.

The site was back online by 1:30 p.m. GMT, though without listings for the H1910 or the H5450.

Online pricing mistakes are common, though companies choose to handle such mistakes in various ways. In January, Amazon canceled thousands of orders for a high-end cell phone that had appeared to be free because of a technical glitch.